Tiffany did 18 more jumping jacks than Ishaan in the morning. Tiffany did 20 jumping jacks. How many jumping jacks did Ishaan do?
Answer: Tiffany did 20 jumping jacks, and Ishaan did 18 fewer than that, so find the difference. The difference is $20 - 18$ jumping jacks. She did $20 - 18 = 2$ jumping jacks.